Support EF Core ExecuteUpdate via IRewritableQueryable

.gitignore

@@ -372,4 +372,6 @@ ReadmeSample.db
 # VitePress docs
 docs/node_modules/
 docs/.vitepress/cache/
-docs/.vitepress/dist/
+docs/.vitepress/dist/
+# Worktrees
+.worktrees/

docs/guide/ef-core-integration.md

@@ -152,6 +152,38 @@ Supported chain-preserving operations:
 - `IgnoreQueryFilters()`, `IgnoreAutoIncludes()`
 - `TagWith(tag)`, `TagWithCallSite()`
 
+## Bulk Updates with ExecuteUpdate
+
+With the `ExpressiveSharp.EntityFrameworkCore.RelationalExtensions` package, you can use modern C# syntax inside `ExecuteUpdate` / `ExecuteUpdateAsync`:
+
+```csharp
+// Requires: .UseExpressives(o => o.UseRelationalExtensions())
+ctx.Orders
+    .ExecuteUpdate(s => s
+        .SetProperty(o => o.Tag, o => o.Price switch
+        {
+            >= 100 => "Premium",
+            >= 50  => "Standard",
+            _      => "Budget"
+        }));
+
+// Async variant
+await ctx.Orders
+    .ExecuteUpdateAsync(s => s.SetProperty(
+        o => o.Tag,
+        o => o.Customer?.Name ?? "Unknown"));
+```
+
+Switch expressions and null-conditional operators inside `SetProperty` value lambdas are normally rejected by the C# compiler in expression tree contexts. The source generator converts them to `CASE WHEN` and `COALESCE` SQL expressions.
+
+::: info
+`ExecuteDelete` works on `IRewritableQueryable<T>` / `ExpressiveDbSet<T>` without any additional setup — it has no lambda parameter, so no interception is needed.
+:::
+
+::: warning
+This feature is available on EF Core 8 and 9. EF Core 10 changed the `ExecuteUpdate` API to use `Action<UpdateSettersBuilder<T>>`, which natively supports modern C# syntax in the outer lambda. For inner `SetProperty` value expressions on EF Core 10, use `ExpressionPolyfill.Create()`.
+:::
+
 ## Plugin Architecture
 
 `UseExpressives()` accepts an optional configuration callback for registering plugins:
@@ -193,7 +225,7 @@ The built-in `RelationalExtensions` package (for window functions) uses this plu
 |---------|-------------|
 | [`ExpressiveSharp`](https://www.nuget.org/packages/ExpressiveSharp/) | Core runtime -- `[Expressive]` attribute, source generator, expression expansion, transformers |
 | [`ExpressiveSharp.EntityFrameworkCore`](https://www.nuget.org/packages/ExpressiveSharp.EntityFrameworkCore/) | EF Core integration -- `UseExpressives()`, `ExpressiveDbSet<T>`, Include/ThenInclude, async methods, analyzers and code fixes |
-| [`ExpressiveSharp.EntityFrameworkCore.RelationalExtensions`](https://www.nuget.org/packages/ExpressiveSharp.EntityFrameworkCore.RelationalExtensions/) | SQL window functions -- ROW_NUMBER, RANK, DENSE_RANK, NTILE (experimental) |
+| [`ExpressiveSharp.EntityFrameworkCore.RelationalExtensions`](https://www.nuget.org/packages/ExpressiveSharp.EntityFrameworkCore.RelationalExtensions/) | Relational extensions -- `ExecuteUpdate`/`ExecuteUpdateAsync` with modern syntax, SQL window functions (ROW_NUMBER, RANK, DENSE_RANK, NTILE) |
 
 ::: info
 The `ExpressiveSharp.EntityFrameworkCore` package bundles Roslyn analyzers and code fixes from `ExpressiveSharp.EntityFrameworkCore.CodeFixers`. These provide compile-time diagnostics and IDE quick-fix actions for common issues like missing `[Expressive]` attributes.

docs/guide/rewritable-queryable.md

@@ -140,6 +140,36 @@ var orders = ctx.Set<Order>()
     .ToList();
 ```
 
+## EF Core: Bulk Updates with ExecuteUpdate
+
+::: info
+Requires the `ExpressiveSharp.EntityFrameworkCore.RelationalExtensions` package and `.UseExpressives(o => o.UseRelationalExtensions())` configuration. Available on EF Core 8 and 9. On EF Core 10+, `ExecuteUpdate` natively accepts delegates — use `ExpressionPolyfill.Create()` for modern syntax in individual `SetProperty` value expressions.
+:::
+
+`ExecuteUpdate` and `ExecuteUpdateAsync` are supported on `IRewritableQueryable<T>`, enabling modern C# syntax inside `SetProperty` value expressions — which is normally impossible in expression trees:
+
+```csharp
+ctx.ExpressiveSet<Product>()
+    .ExecuteUpdate(s => s
+        .SetProperty(p => p.Tag, p => p.Price switch
+        {
+            > 100 => "premium",
+            > 50  => "standard",
+            _     => "budget"
+        })
+        .SetProperty(p => p.Category, p => p.Category ?? "Uncategorized"));
+```
+
+This generates a single SQL `UPDATE` with `CASE WHEN` and `COALESCE` expressions — no entity loading required.
+
+`ExecuteDelete` works out of the box on `IRewritableQueryable<T>` without any stubs (it has no lambda parameter):
+
+```csharp
+ctx.ExpressiveSet<Product>()
+    .Where(p => p.Price switch { < 10 => true, _ => false })
+    .ExecuteDelete();
+```
+
 ## IAsyncEnumerable Support
 
 `IRewritableQueryable<T>` supports `AsAsyncEnumerable()` for streaming results:

src/ExpressiveSharp.EntityFrameworkCore.RelationalExtensions/Extensions/RewritableQueryableRelationalExtensions.cs

@@ -0,0 +1,56 @@
+#if !NET10_0_OR_GREATER
+using System.ComponentModel;
+using System.Diagnostics;
+using ExpressiveSharp;
+using Microsoft.EntityFrameworkCore.Query;
+
+// ReSharper disable once CheckNamespace — intentionally in Microsoft.EntityFrameworkCore for discoverability
+namespace Microsoft.EntityFrameworkCore;
+
+/// <summary>
+/// Extension methods on <see cref="IRewritableQueryable{T}"/> for EF Core bulk update operations.
+/// These stubs are intercepted by the ExpressiveSharp source generator via <see cref="PolyfillTargetAttribute"/>
+/// to forward to the appropriate EF Core ExecuteUpdate method.
+/// </summary>
+/// <remarks>
+/// Only available on EF Core 8/9. In EF Core 10+, <c>ExecuteUpdate</c> uses <c>Action&lt;UpdateSettersBuilder&lt;T&gt;&gt;</c>
+/// which natively supports modern C# syntax in the outer lambda. For inner <c>SetProperty</c> value expressions,
+/// use <c>ExpressionPolyfill.Create()</c> to enable modern C# syntax.
+/// </remarks>
+[EditorBrowsable(EditorBrowsableState.Never)]
+public static class RewritableQueryableRelationalExtensions
+{
+    private const string InterceptedMessage =
+        "This method must be intercepted by the ExpressiveSharp source generator. " +
+        "Ensure the generator package is installed and the InterceptorsNamespaces MSBuild property is configured.";
+
+    // ── Bulk update methods (intercepted) ────────────────────────────────
+    // EF Core 8: ExecuteUpdate lives on RelationalQueryableExtensions (Relational package)
+    // EF Core 9: ExecuteUpdate moved to EntityFrameworkQueryableExtensions (Core package)
+
+#if NET9_0
+    [PolyfillTarget(typeof(EntityFrameworkQueryableExtensions))]
+#else
+    [PolyfillTarget(typeof(RelationalQueryableExtensions))]
+#endif
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public static int ExecuteUpdate<TSource>(
+        this IRewritableQueryable<TSource> source,
+        Func<SetPropertyCalls<TSource>, SetPropertyCalls<TSource>> setPropertyCalls)
+        where TSource : class
+        => throw new UnreachableException(InterceptedMessage);
+
+#if NET9_0
+    [PolyfillTarget(typeof(EntityFrameworkQueryableExtensions))]
+#else
+    [PolyfillTarget(typeof(RelationalQueryableExtensions))]
+#endif
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public static Task<int> ExecuteUpdateAsync<TSource>(
+        this IRewritableQueryable<TSource> source,
+        Func<SetPropertyCalls<TSource>, SetPropertyCalls<TSource>> setPropertyCalls,
+        CancellationToken cancellationToken = default)
+        where TSource : class
+        => throw new UnreachableException(InterceptedMessage);
+}
+#endif

src/ExpressiveSharp.Generator/Emitter/ReflectionFieldCache.cs

@@ -64,7 +64,22 @@ public string EnsureMethodInfo(IMethodSymbol method)
             var paramCount = originalDef.Parameters.Length;
             var typeArgs = string.Join(", ", method.TypeArguments.Select(t =>
                 $"typeof({ResolveTypeFqn(t)})"));
-            return $"global::System.Linq.Enumerable.First(global::System.Linq.Enumerable.Where(typeof({typeFqn}).GetMethods({flags}), m => m.Name == \"{method.Name}\" && m.IsGenericMethodDefinition && m.GetGenericArguments().Length == {genericArity} && m.GetParameters().Length == {paramCount})).MakeGenericMethod({typeArgs})";
+
+            // Disambiguate overloads that share name, generic arity, and parameter count
+            // (e.g., SetProperty<P>(Func<T,P>, P) vs SetProperty<P>(Func<T,P>, Func<T,P>))
+            // by checking whether each parameter is a generic type or a type parameter.
+            var paramChecksBuilder = new System.Text.StringBuilder();
+            for (int i = 0; i < originalDef.Parameters.Length; i++)
+            {
+                var paramType = originalDef.Parameters[i].Type;
+                if (paramType is ITypeParameterSymbol)
+                    paramChecksBuilder.Append($" && !m.GetParameters()[{i}].ParameterType.IsGenericType");
+                else if (paramType is INamedTypeSymbol { IsGenericType: true })
+                    paramChecksBuilder.Append($" && m.GetParameters()[{i}].ParameterType.IsGenericType");
+            }
+            var paramChecks = paramChecksBuilder.ToString();
+
+            return $"global::System.Linq.Enumerable.First(global::System.Linq.Enumerable.Where(typeof({typeFqn}).GetMethods({flags}), m => m.Name == \"{method.Name}\" && m.IsGenericMethodDefinition && m.GetGenericArguments().Length == {genericArity} && m.GetParameters().Length == {paramCount}{paramChecks})).MakeGenericMethod({typeArgs})";
         }
         else
         {

tests/ExpressiveSharp.EntityFrameworkCore.RelationalExtensions.Tests/ExecuteUpdateIntegrationTests.cs

@@ -0,0 +1,172 @@
+#if !NET10_0_OR_GREATER
+using ExpressiveSharp.EntityFrameworkCore.RelationalExtensions.Tests.Models;
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+
+namespace ExpressiveSharp.EntityFrameworkCore.RelationalExtensions.Tests;
+
+/// <summary>
+/// End-to-end integration tests for ExecuteUpdate via IRewritableQueryable.
+/// These prove that modern C# syntax (null-conditional, switch expressions)
+/// inside SetProperty value expressions works with real SQL execution — functionality
+/// that is impossible with normal C# expression trees.
+/// </summary>
+[TestClass]
+public class ExecuteUpdateIntegrationTests
+{
+    private SqliteConnection _connection = null!;
+
+    [TestInitialize]
+    public void Setup()
+    {
+        _connection = new SqliteConnection("Data Source=:memory:");
+        _connection.Open();
+    }
+
+    [TestCleanup]
+    public void Cleanup()
+    {
+        _connection.Dispose();
+    }
+
+    private ExecuteUpdateTestDbContext CreateContext()
+    {
+        var options = new DbContextOptionsBuilder<ExecuteUpdateTestDbContext>()
+            .UseSqlite(_connection)
+            .UseExpressives(o => o.UseRelationalExtensions())
+            .Options;
+        var ctx = new ExecuteUpdateTestDbContext(options);
+        ctx.Database.EnsureCreated();
+        return ctx;
+    }
+
+    private static void SeedProducts(ExecuteUpdateTestDbContext ctx)
+    {
+        ctx.Products.AddRange(
+            new Product { Id = 1, Name = "Widget", Category = "A", Tag = "", Price = 150, Quantity = 10 },
+            new Product { Id = 2, Name = "Gadget", Category = "B", Tag = "", Price = 75, Quantity = 5 },
+            new Product { Id = 3, Name = "Doohickey", Category = null, Tag = "", Price = 30, Quantity = 20 });
+        ctx.SaveChanges();
+    }
+
+    /// <summary>
+    /// Basic test: verify the generator intercepts ExecuteUpdate and forwards to EF Core.
+    /// </summary>
+    [TestMethod]
+    public void ExecuteUpdate_BasicConstant_Works()
+    {
+        using var ctx = CreateContext();
+        SeedProducts(ctx);
+
+        var affected = ctx.ExpressiveProducts
+            .ExecuteUpdate(s => s.SetProperty(p => p.Tag, "basic"));
+
+        Assert.AreEqual(3, affected);
+        // ExecuteUpdate bypasses change tracker — use AsNoTracking to see actual DB state
+        var products = ctx.Products.AsNoTracking().OrderBy(p => p.Id).ToList();
+        Assert.AreEqual("basic", products[0].Tag);
+        Assert.AreEqual("basic", products[1].Tag);
+        Assert.AreEqual("basic", products[2].Tag);
+    }
+
+    /// <summary>
+    /// Proves new capability: switch expression inside SetProperty value lambda.
+    /// <c>o.Price switch { > 100 => "premium", > 50 => "standard", _ => "budget" }</c>
+    /// is impossible in a normal C# expression tree context.
+    /// </summary>
+    [TestMethod]
+    public void ExecuteUpdate_SwitchExpression_TranslatesToSql()
+    {
+        using var ctx = CreateContext();
+        SeedProducts(ctx);
+
+        ctx.ExpressiveProducts
+            .ExecuteUpdate(s => s.SetProperty(
+                p => p.Tag,
+                p => p.Price switch
+                {
+                    > 100 => "premium",
+                    > 50 => "standard",
+                    _ => "budget"
+                }));
+
+        var products = ctx.Products.AsNoTracking().OrderBy(p => p.Id).ToList();
+        Assert.AreEqual("premium", products[0].Tag);   // Price=150
+        Assert.AreEqual("standard", products[1].Tag);   // Price=75
+        Assert.AreEqual("budget", products[2].Tag);      // Price=30
+    }
+
+    /// <summary>
+    /// Proves new capability: null-coalescing operator inside SetProperty value lambda.
+    /// </summary>
+    [TestMethod]
+    public void ExecuteUpdate_NullCoalescing_TranslatesToSql()
+    {
+        using var ctx = CreateContext();
+        SeedProducts(ctx);
+
+        ctx.ExpressiveProducts
+            .ExecuteUpdate(s => s.SetProperty(
+                p => p.Tag,
+                p => p.Category ?? "UNKNOWN"));
+
+        var products = ctx.Products.AsNoTracking().OrderBy(p => p.Id).ToList();
+        Assert.AreEqual("A", products[0].Tag);       // Category="A"
+        Assert.AreEqual("B", products[1].Tag);       // Category="B"
+        Assert.AreEqual("UNKNOWN", products[2].Tag); // Category=null
+    }
+
+    /// <summary>
+    /// Proves that multiple SetProperty calls with modern C# syntax work together,
+    /// producing multiple SET clauses in a single SQL UPDATE statement.
+    /// </summary>
+    [TestMethod]
+    public void ExecuteUpdate_MultipleProperties_WithModernSyntax()
+    {
+        using var ctx = CreateContext();
+        SeedProducts(ctx);
+
+        ctx.ExpressiveProducts
+            .ExecuteUpdate(s => s
+                .SetProperty(p => p.Tag, p => p.Price switch
+                {
+                    > 100 => "expensive",
+                    _ => "moderate"
+                })
+                .SetProperty(p => p.Category, "updated"));
+
+        var products = ctx.Products.AsNoTracking().OrderBy(p => p.Id).ToList();
+        Assert.AreEqual("expensive", products[0].Tag);    // Price=150
+        Assert.AreEqual("updated", products[0].Category);
+        Assert.AreEqual("moderate", products[1].Tag);      // Price=75
+        Assert.AreEqual("updated", products[1].Category);
+        Assert.AreEqual("moderate", products[2].Tag);      // Price=30
+        Assert.AreEqual("updated", products[2].Category);
+    }
+
+    /// <summary>
+    /// Proves async variant works end-to-end with modern C# syntax.
+    /// </summary>
+    [TestMethod]
+    public async Task ExecuteUpdateAsync_SwitchExpression_TranslatesToSql()
+    {
+        using var ctx = CreateContext();
+        SeedProducts(ctx);
+
+        await ctx.ExpressiveProducts
+            .ExecuteUpdateAsync(s => s.SetProperty(
+                p => p.Tag,
+                p => p.Price switch
+                {
+                    > 100 => "premium",
+                    > 50 => "standard",
+                    _ => "budget"
+                }));
+
+        var products = await ctx.Products.AsNoTracking().OrderBy(p => p.Id).ToListAsync();
+        Assert.AreEqual("premium", products[0].Tag);
+        Assert.AreEqual("standard", products[1].Tag);
+        Assert.AreEqual("budget", products[2].Tag);
+    }
+}
+#endif

tests/ExpressiveSharp.EntityFrameworkCore.RelationalExtensions.Tests/Models/ExecuteUpdateTestDbContext.cs

@@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace ExpressiveSharp.EntityFrameworkCore.RelationalExtensions.Tests.Models;
+
+public class Product
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = "";
+    public string? Category { get; set; }
+    public string Tag { get; set; } = "";
+    public double Price { get; set; }
+    public int Quantity { get; set; }
+}
+
+public class ExecuteUpdateTestDbContext : DbContext
+{
+    public DbSet<Product> Products => Set<Product>();
+    public ExpressiveDbSet<Product> ExpressiveProducts => this.ExpressiveSet<Product>();
+
+    public ExecuteUpdateTestDbContext(DbContextOptions<ExecuteUpdateTestDbContext> options) : base(options)
+    {
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        modelBuilder.Entity<Product>(entity =>
+        {
+            entity.HasKey(e => e.Id);
+        });
+    }
+}